EP4368311A1 - Immersion nozzle - Google Patents

Immersion nozzle Download PDF

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Publication number
EP4368311A1
EP4368311A1 EP21949359.0A EP21949359A EP4368311A1 EP 4368311 A1 EP4368311 A1 EP 4368311A1 EP 21949359 A EP21949359 A EP 21949359A EP 4368311 A1 EP4368311 A1 EP 4368311A1
Authority
EP
European Patent Office
Prior art keywords
section
openings
flow channel
cross
flow
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP21949359.0A
Other languages
German (de)
English (en)
French (fr)
Inventor
Kanae Nishio
Hiroyasu NIITSUMA
Riccardo CONTE
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Danieli and C Officine Meccaniche SpA
Original Assignee
Danieli and C Officine Meccaniche SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Danieli and C Officine Meccaniche SpA filed Critical Danieli and C Officine Meccaniche SpA
Publication of EP4368311A1 publication Critical patent/EP4368311A1/en
Pending legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/50—Pouring-nozzles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal

Definitions

  • the present invention relates to an immersion nozzle to be used to continuously cast thin slabs.
  • Patent Document 1 JP H08-039208A
  • the immersion nozzle described in Patent Document 1 it is possible to prevent sticking of base metal that occurs between the immersion nozzle and a mold wall and skinning on a molten metal surface that occurs near the short sides of a wide mold, as well as the occurrence of a molten metal suction phenomenon, remelting of a solidifying shell, and the like.
  • the immersion nozzle described in Patent Document 1 sufficiently suppresses skinning in a meniscus part.
  • An immersion nozzle is an immersion nozzle having a flow channel and openings; the immersion nozzle comprising: a first section; a connection section; and a second section, the first section, the connection section, and the second section being provided in this order from a base end side, wherein the flow channel in the first section has a lateral cross-sectional shape that is a circular shape, the flow channel in the second section has a lateral cross-sectional shape that is a rectangular shape, the flow channel in the connection section has a shape with which the flow channel in the first section is continuously connected to the flow channel in the second section, the rectangular shape of the second section has long sides each having a length a and short sides each having a length b, with a ratio a/b between the length a and the length b being 3 or greater and 7 or less, the flow channel in the second section has a cross-sectional area S 2 , the flow channel in the first section has a cross-sectional area S 1 , and the cross-sectional area S 2 is
  • each of the first openings has an opening area S 3 in a corresponding one of the side faces
  • each of the second openings has an opening area S 4 in a corresponding one of the side faces and an opening area S 5 in the bottom face
  • the opening areas S 3 , S 4 , and S 5 satisfy expressions (1) and (2) below: S 4 ⁇ S 5 S 4 + S 5 / S 3 ⁇ 1.5
  • a discharge flow discharged from the nozzle hits a short side of the mold and separates into an upward flow and a downward flow.
  • the upward flow is excessively strong, powder entrainment or the like is likely to occur, while if the downward flow is excessively strong, inclusions, bubbles, or the like is unlikely to rise to the surface.
  • the balance between the upward flow and the downward flow is optimized, and an excessive meniscus flow can be suppressed.
  • each of the first openings has an opening area S 3 in a corresponding one of the side faces and an opening area S 6 on a flow channel side, and the opening area S 3 is smaller than the opening area S 6 .
  • the immersion nozzle has a largest width of 300 mm or less.
  • the nozzle 1 is a tubular member made of a refractory material.
  • a flow channel for allowing molten steel to flow is formed inside the nozzle 1, which has openings 5 at a leading end.
  • the nozzle 1 has a first section 2, a connection section 3, and a second section 4 in this order from a base end side, and these sections have different shapes ( FIGS. 1 and 2 ).
  • the nozzle 1 is joined to upstream equipment (such as a stopper or a sliding nozzle; not shown) at the first section 2, and molten steel flowing from the upstream equipment flows through the flow channel.
  • the second section 4 includes the openings 5 (first openings 51 and second openings 52), from which the molten steel flows out to a mold (not shown).
  • the type of refractory material that constitutes the nozzle 1 is not specifically limited, and may be any refractory material conventionally used in this field.
  • refractory materials include alumina-graphite, magnesia-graphite, spinel-graphite, zirconia-graphite, calcium zirconate-graphite, high-alumina, alumina-silica, silica, zircon, and spinel. Zone lining may also be applied as appropriate.
  • a cross section of the flow channel refers to a cross section in a direction orthogonal to the above-defined up-down direction (a direction orthogonal to the paper plane of FIG. 1 ), and this cross section is referred to as a lateral cross section, unless otherwise stated.
  • this cross section is referred to as a lateral cross section, unless otherwise stated.
  • the above-defined lateral cross section is also a cross section relative to the flow direction of the molten steel.
  • the first section 2 is a main section on the base end side of the nozzle 1.
  • the lateral cross section of a flow channel 21 in the first section 2 has a circular shape ( FIGS. 1 to 3 ).
  • the circular shape as used herein is not limited to a circular shape in the mathematical sense, and may be a shape that can be dealt with as a substantially circular shape. Accordingly, a deviation (tolerance etc.) from a mathematically circular shape that may occur in an attempt to realize a circular shape as an industrial product is acceptable.
  • a cross-sectional area S 1 of the flow channel 21 in this embodiment is 6000 mm 2 .
  • the second section 4 is a main section on the leading end side of the nozzle 1.
  • the lateral cross section of a flow channel 41 in the second section 4 has a rectangular shape ( FIGS. 1 , 2 and 4 ).
  • the rectangular shape as used herein is not limited to a rectangular shape in the mathematical sense, and may be a shape that can be dealt with as a substantially rectangular shape. Accordingly, deformation (chamfering etc.) that is ordinarily applied in an attempt of realizing a rectangular shape as an industrial product may be imparted, and a deviation (tolerance etc.) from a mathematically rectangular shape is acceptable.
  • a cross-sectional area S 2 of the flow channel 41 in this embodiment is 10000 mm 2 . Accordingly, the cross-sectional area S 2 of the flow channel 41 is greater than the cross-sectional area S 1 of the flow channel 21.
  • the flow velocity of molten steel discharged from the openings 5 is reduced by thus making the cross-sectional area in the downstream area (flow channel 41) larger than the cross-sectional area in the upstream area (flow channel 21). This causes an upward flow in the mold and suppresses an excessive meniscus flow.
  • the rectangle has long sides 42 each having a length a of 200 mm, and short sides 43 each having a length b of 50 mm ( FIG. 4 ).
  • the ratio a/b between the lengths a and b is 4.0.
  • numerical values of the rectangular shape are not limited to the above values and may be changed in the range of the ratio a/b from 3 to 7. If the ratio a/b is changed, both the length a of the long sides 42 and the length of the short sides 43 of the rectangular shape may be changed. Meanwhile, the length b of the short sides 43 is restricted by the length of the short sides of the mold, and the length a of the long sides 42 is, therefore, more flexible in general.
  • the ratio a/b being in the range from 3 to 7 makes a molten steel flow unlikely to detach from the wall face of the flow channel 41 and allows for an appropriate flow.
  • the ratio a/b being less than 3 makes the length a of the long sides 42 excessively small and makes it difficult to secure an inner tube cross-sectional area necessary for casting.
  • the ratio a/b being greater than 7 makes the length a of the long sides 42 excessively large and makes the weight of the nozzle 1 more likely to increase, which may increase the load of a worker or a device that handles the nozzle 1.
  • the ratio a/b being greater than 7 may cause the flow channel 31 to be steeply deformed in the longitudinal direction of the connection section 3 and may detach the molten steel flow from the wall face of the flow channel.
  • the lateral cross-sectional shape of the substantial part (refractory material part) of the second section 4 also has a rectangular shape in correspondence with the rectangular shape of the lateral cross section of the flow channel 41.
  • the second section 4 has a bottomed rectangular column shape.
  • a face of the rectangular shape that corresponds to each long side 42 has a width W of 270 mm, which is the largest width of the nozzle 1.
  • the largest width W of the nozzle 1 thus being less than 300 mm improves workability when implementing work to replace the nozzle 1 using a quick changer, which is favorable. This is because the largest width W of the nozzle 1 being less than 300 mm makes it easier to secure room for the work to replace the nozzle 1 within the mold due to the dimensional relationship between the nozzle 1 and the mold.
  • the first openings 51 are open in side faces 44 of the second section 4 that correspond to the short sides 43 of the rectangular shape ( FIGS. 1 and 5 ).
  • Two first openings 51 are provided.
  • the two first openings 51 (51A and 51B) are open in two side faces 44 (44A and 44B) corresponding to two short sides 43 (43A and 43B) in one-to-one correspondence.
  • the first openings 51 being open in the side faces 44 allow the molten steel flow to be discharged toward the short sides of the mold. This can cause an upward flow in the mold and promote heat supply to a meniscus.
  • two second openings 52 are open while extending between the side faces 44 and a bottom face 45, which is a face of the second section 4 at the leading end in the longitudinal direction ( FIGS. 1 , 5 and 6 ).
  • one second opening 52A is open while extending between the side face 44A (one side face) and the bottom face 45
  • the other second opening 52B is open while extending between the side face 44B (the other side face) and the bottom face 45.
  • the second openings 52 being open in the above mode allow the molten steel flow to be discharged to the lower side of the mold and enable appropriate distribution of the molten steel flow in the mold.
  • an opening area S 3 of each first opening 51 in the corresponding side face 44 (the area of the first opening 51 shown in FIG. 5 ) is 2700 mm 2 .
  • An opening area S 4 of each second opening 52 in the corresponding side face 44 (the area of the second opening 52 shown in FIG. 5 ) is 2000 mm 2 , and an opening area S 5 thereof in the bottom face 45 (the area of the second opening 52 shown in FIG. 6 ) is 5000 mm 2 .
  • the first openings 51 and the second openings 52 having the opening areas that satisfy the expressions (1) and (2) can optimize the balance between the upward flow and the downward flow and suppress an excessive meniscus flow.
  • the opening area S 3 of the first openings 51 and the opening areas S 4 and S 5 of the second openings 52 are not limited to the above values and may be changed as long as the expressions (1) and (2) are satisfied.
  • an opening area S 6 of each first opening 51 on the flow channel 41 side is 4000 mm 2 . Accordingly, the opening area S 3 of each first opening 51 in the side face 44 is smaller than the opening area S 6 on the flow channel 41 side.
  • connection section 3 is a section that continuously connects the first section 2 to the second section 4 ( FIGS. 1 and 2 ).
  • the connection section 3 includes a flow channel 31 having a shape that continuously connects the flow channel 21 in the first section 2 having a circular cross-sectional shape to the flow channel 41 in the second section 4 having a rectangular cross-sectional shape.
  • the cross-sectional shape of the flow channel 31 is, therefore, circular at an upper end 32 and rectangular at a lower end 33.
  • the immersion nozzle according to the present invention need not satisfy at least either the expressions (1) or (2), and S 3 may be greater than S 6 .
  • the largest width W of the nozzle 1 is 270 mm, which is less than 300 mm.
  • the largest width of the immersion nozzle according to the present invention may be 300 mm or greater.
  • Nozzles with various dimensional conditions were designed, and numerical fluid dynamics calculations were performed for modes of discharged molten steel flow using fluid analysis software PHOENICS produced by CHAM-japan.
  • the dimensional conditions for examples and comparative examples are as listed in Tables 1 below.
  • Flow velocity contour plots were output based on the calculation results. Note that the following parameters were applied in the calculations.
  • Meniscus flow velocities were identified based on the output flow velocity contour plots for the examples and comparative examples. The results were evaluated on a three-point scale from A to C, according to the value of meniscus velocity.
  • the output flow velocity contour plots were visually checked to identify the occurrence of detachment of the molten steel flow in the second section 4, and the results were judged (A or C).
  • the output flow velocity contour plots were visually checked to identify the presence and extent of a suction flow in the first openings 51.
  • the results were evaluated on a three-point scale from A to C, according to the observed states.
  • Table 1 shows the dimensional conditions and evaluation results for the examples and comparative examples.
  • the evaluation result regarding detachment of the molten steel flow was A.
  • the evaluation result regarding detachment of the molten steel flow was C.
  • the examples 1 to 6 where S 2 was greater than S 1 , the meniscus flow velocity was within an appropriate range (rated A or B).
  • the meniscus flow velocity was not in a favorable range (rated C).
  • S 3 and S 6 - S 3 S 6 S 3 > S 6 S 3 > S 6 S 3 > S 6 S 3 ⁇ S 6 S 3 ⁇ S 6 S 3 > S 6 S 3 > S 6 Meniscus flow velocity B B A A A A C C Detachment of molten steel flow A A A A A A A A C A Suction flow in first opening B B B B A A C C
  • the present invention can be used in an immersion nozzle for thin-slab continuous casting, for example.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
EP21949359.0A 2021-07-09 2021-07-09 Immersion nozzle Pending EP4368311A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2021/025890 WO2023281726A1 (ja) 2021-07-09 2021-07-09 浸漬ノズル

Publications (1)

Publication Number Publication Date
EP4368311A1 true EP4368311A1 (en) 2024-05-15

Family

ID=84800580

Family Applications (1)

Application Number Title Priority Date Filing Date
EP21949359.0A Pending EP4368311A1 (en) 2021-07-09 2021-07-09 Immersion nozzle

Country Status (8)

Country Link
US (1) US20240238869A1 (ko)
EP (1) EP4368311A1 (ko)
JP (1) JP7427138B2 (ko)
KR (1) KR20240034747A (ko)
CN (1) CN117580657A (ko)
CA (1) CA3223418A1 (ko)
MX (1) MX2024000289A (ko)
WO (1) WO2023281726A1 (ko)

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0839208A (ja) 1994-07-26 1996-02-13 Sumitomo Metal Ind Ltd 広幅薄スラブ鋳造用浸漬ノズル
JP3322647B2 (ja) * 1999-02-09 2002-09-09 東芝セラミックス株式会社 薄スラブ鋳造用扁平ノズル
JP4079415B2 (ja) * 2002-04-26 2008-04-23 黒崎播磨株式会社 薄スラブ連続鋳造用浸漬ノズル
JP5047854B2 (ja) * 2008-03-27 2012-10-10 黒崎播磨株式会社 連続鋳造用浸漬ノズル
JP5645736B2 (ja) * 2011-03-31 2014-12-24 黒崎播磨株式会社 連続鋳造用浸漬ノズル

Also Published As

Publication number Publication date
MX2024000289A (es) 2024-02-01
WO2023281726A1 (ja) 2023-01-12
US20240238869A1 (en) 2024-07-18
CA3223418A1 (en) 2023-01-12
CN117580657A (zh) 2024-02-20
KR20240034747A (ko) 2024-03-14
JPWO2023281726A1 (ko) 2023-01-12
JP7427138B2 (ja) 2024-02-02

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